Activate Woe Strider by sacrificing Master of the Veil.
When Master of the Veil dies, Yarus' second ability triggers, returning Master of the Veil from your graveyard to the battlefield face down, then turning it face up.
Master of the Veil triggers, turning itself face down.
Resolve the Woe Strider ability, causing you to scry 1.
Repeat.
This intricate loop relies on Yarus, Roar of the Old Gods as its engine, transforming a tragic sacrifice into a miraculous return. By using Woe Strider to sacrifice Master of the Veil, you trigger Yarus's ability to resurrect that creature face down and immediately flip it face up. That very morph-based manifestation triggers Master of the Veil's own ability, turning itself face down once again and resetting the stage so Woe Strider can repeat the sacrifice ad infinitum.